She was struck around teatime this evening by a car in Bangor’s Irvine Park off the ring road in the Co Down town.
Her death brings to 29 the number of people killed on Northern Ireland’s road so far this year.
Police in Bangor are appealing for witnesses to the accident.
Sergeant Brian Shankey said, “The collision took place shortly after 5pm and involved a grey coloured Hyundai car.
“The driver of the car has been spoken to by police and is helping with our enquiries.
“The young girl was taken by ambulance to hospital following the collision, but died from her injuries.
“I would appeal to anyone who was in the area of Irvine Park and has any information which may assist us with our enquiries to contact police at Bangor on 101.”
North Down DUP MLA Gordon Dunne tweeted this evening: “Shocked and saddened at the death of a young girl in Bangor today.
“Thoughts and prayers are with her family.”